Method of installing a clinch nut



June 8, 1965 P. E. DOUBLE METHOD OF INSTALLING A CLINCH NUT OriginalFiled June 25, 1962 2 Sheets-Sheet 1 PLUM/1E1? ED041345 BY 4r Tax/var}June 8, 1965 P. E. DOUBLE 3,187,427

METHOD OF INSTALLING A CLINCH NUT Original Filed June 25, 1962 2Sheets-Sheet 2 INVENTOR.

Pwnnsa E. DOUBLE BY United States Patent 0 Claims. (Cl. 29-509) Thisapplication is a division of my copending earlier filed United Statesapplication SerialNo. 204,854, filed June 25, 1962.

The present invention relates to a method of afiixing a nut capable ofserving as either a pierce nut or clinch nut to a panel by either apiercing or clinching operation by deforming the panel or the nut,respectively.

In the manufactureof products, such as appliances, automobiles, and thelike, from sheet metal panels, it is often necessary to attach adjacentpanels to one another or to attach brackets or the like to a panel. Toaccommodate the utilization of bolts and other threaded fasteners tosuch assembly operations, there have been developed various means forsecuring a nut to a panel. Two general types of nuts are utilized forthis purpose. One such type of nut is a clinch nut of the typeillustrated in Patent No. 2,183,641. To utilize such a nut, an apertureis formed in the panel, the nut is positioned against the panel with apilot portion of the nut projecting through the aperture, and the pilotportion is staked outwardly so that the peripheral portions of the nutoverhang the aperture in the plate. A second form of nut, commonly knownas a pierce nut, is illustrated in Patent No. 2,707,- 322. Here, the nutserves as the punch and is forced through the panel or plate to form itsown hole. The nut is provided with undercut grooves into which the panelis deformed by a die operation to secure the nut to the panel or plate.1

While these two types of nuts are interchangeable in use, i.e. toprovide for securing a bolt or other threaded fastener to the panel bymeans of the nut, conventional clinch nuts and pierce nuts are notinterchangeable in the sense that the same nuts can be used for eitherfunction. The clinch'nut does not have an undercut groove into which themetal can be deformed or swaged, while the pierce nut does not fitwithin a pro-pierced hole so as to be accurately clinched in position,due to the undercut grooves therein.

Obviously, substantial advantages could be obtained by utilizing asingle nut structure capable of functioning as either a clinch nut or apierce nut, depending upon the specific application, the manner ofinstallation, and other process or product variables.

The method of thepresent invention provides such a single nut capable ofinterchangeable utility as either a clinch nut or a pierce nut. Thisdual function is obtained by merely utilizing a pierce nut havingundercut grooves of a specific configuration and serving to firmlylocate the pilot portion of the nut in a preformed hole to retain thenut in position for a subsequent staking operation. At the same time,the undercut grooves of the pierce not are capable of receiving thereinportions of the panel swaged thereinto by utilization of a conventionalswaging die. i

specific nut configuration, islocated between a massive piercingshoulder formed on the pilot portion of the nut and the laterallyprojecting shoulders extending beyond the pilot portionand serving tobottom the nut on the panel to which it is to be affiXed. Immediatelyadjacent each of the flanges there is located a pilot base ledgecoextensive with the nut flange and coplanar with the pierc- Theparticular grooveconfiguration, as applied to a ice cated the undercutgroove.

In utilizing the nut, it is obvious that the pro-pierced hole must becapable of accommodatingpassage of the nutpilot portion thereinto, theledge then also enters the" hole and serves to center the nut in thehole for a subsequent staking operation. Similarly, when the nut isutilized as a pierce nut, the aperture which is pierced in the panel isof substantially the same dimension as the pilot portion shoulder, sothat the ledge again will snugly fit within the punched aperture.

When the nut is utilized as a clinch nut, the staking operation occursat the corners of the nut shoulder, the nut metal being deformedoutwardly to overlie the edges of the panel aperture. In utilizing a nutof the present invention, the staking operation is carried outto such anextent that nut metal flows into the nut grooves and forms a tightinterconnection between the nut and the edges of the panel aperture.Thus, the staking operation performed upon the clinch nut serves to fillor close up the pierce nut grooves at the regions of staking and anextremely tight nut-panel fit is obtained.

When the nut is utilized as a pierce nut, the locating ledge at theextremity of the groove serves to 'fill the lower portions of thegroove, which are the most difi icult portions normally to fill withmaterial swaged from the sheet metal panel. Also, the ledge aids indirecting the swaged panel metal into the groove so that the groove iscompletely filled with s-Waged metal, thus resulting in improved piercenut-panel assembly.

It is, therefore, an important object of themethod of the presentinvention to provide an improved nu't capable of being utilized aseither a pierce nut or a clinch nut.

Another important object of the method of this invention is theprovision of a nut provided with undercut grooves of specificconfiguration and adapating the nut for utility as either a pierce nutor a clinch nut,the groove configuration aiding in locating the adjacentnut pilot portion in a pre-pierced hole (when the nut is utilized as aclinch nut) and aiding to fill the grooves with swaged metal from thepanel (when the nut is utilized as a pierce nut).

It is a further important object of thisinvention to pro Vide animproved method of securing a nut in a prepierced holein a sheet metalpanel, the nut having a pilot portion projecting through the pre-piercedhole and a groovepositioned in the hole, the nut pilot portion beingsubsequently deformed to eilect metal flow over the edges of the holeand to fill thenut grooves at those locations of thenut at which it isdeformed.

It is an additional, and no less important, object of the method of thisinvention to provide a novel nut having laterally extending shouldersand a reduced polygonal pilot portion joined to the shoulders throughside walls provided with undercut grooves, the side Walls having a ledgesurface adjacent the shoulders and coplanar with the pilot portion, theledges serving to locate the nut pilot portion in the panel aperturewhen the nut is utilized as a clinch nut and serving to direct the flowof swaged metal into the grooves when the nut is' utilized as a piercenut.

Other objects'of this invention will appear in the following descriptionand appendedclaims, reference being had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignatecorresponding parts in the severalviewa 2 On the drawings: j g

FIGURE 1 is a perspective view'illustrating a nut of the presentinvention; 1 't j 7 FIGURE 2 is a fragmentary enlarged sectional viewfurther illustrating the nut and particularly the groove thereof;

FIGURE 3 is a sectional view illustrating utilization of the nut as apierce nut;

FIGURE 4 is a perspective view illustrating utilization of the nut as aclinch nut; and

FIGURE 5 is a sectional view similar to FIGURE 3 illustrating theclinching of the nut into position.

Before explaining the present invention in detail, it is to beunderstood that the invention is not limited in its application to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings, since the invention is capable of otherembodiments and of being practiced or carried out in various ways. Also,it is to be understood that the phraseology or terminology employedherein is for the purpose of description and not of limitation.

As shown on the drawings:

In FIGURE 1, reference numeral refers generally to a nut of the presentinvention. This nut 10 is a rolled shape and is made in continuous stripform, the individual nuts 10 being severed from such a strip andsimultaneously punched to form a blank aperture, this aperture laterbeing tapped by conventional tapping methods.

It will be noted that the nut 10 is polygonal in shape, preferablyrectangular and has a massive body 11 from which a reduced upper pilotportion 12 projects. The massive body 11 includes, in the orientation ofFIGURE 1, a planar bottom surface 13 and a pair of laterally projectingflanges 14 having upper stop surfaces 15 which normally abut one surfaceof the panel to which the nut is afiixed, as will be hereafter morefully described.

The upper surface 16 of the nut is also planar and is provided withperimetric or peripheral shearing edges 17 extending along the planarside surfaces 18 of the nut and additional shearing edges 19 overlyingthose edges of the nut provided with the flanges 14. The nut pilotportion 12 and the nut body portion 11 both encompass a centrallylocated threaded aperture 20 adapted for the reception of a bolt orsimilar threaded fastener.

The piercing edges 19 are contiguous with and form one edge of nutshoulders 21. These shoulders 21 are of substantial size in order towithstand the punching force exerted by the nut when it is utilized as apierce nut. These flanges 21 have exposed rectangular side surfaces 22which lie parallel to the axis of the aperture 20.

One novel feature of the present invention resides in a ledge or pilotsurface 25 which is coplanar with the side surfaces 22 of the shoulders21 of the pilot portion 12 of the nut. This ledge surface is defined byone edge 26, common to the shoulder surface 15 and the ledge surface 25,and by an upper edge 27 located between the flange surface 15 andshoulder 21. As best illustrated in FIG- .URE 2 of the drawings, thesurface 25 is coplanar with the edge surface 22 of the shoulder 21 for apurpose to be hereinafter more fully described.

The edge 27 defining that extremity of the surface 25 spaced from theflange surface 15 is common to the surface 25 and to an inclined surface29. This surface 29 is inclined toward the overlying shoulder 21 andtoward the axis of the threaded aperture 20 to define with theoverhanging shoulder a groove indicated generally at 30. The surface 29terminates in a flat surface 31 lying generally parallel to the surfaces25 and 22 and joined to the surface 22 by means of a planar undersurface32 parallel to the exposed surface 16 of the nut pilot portion 12.

Also, as illustrated in FIGURE 2 of the drawings, there is illustratedthe dimensional relationship between the surfaces 22 and 25 and thegroove 30. The dimension denoted A is defined as the pilot height of thenut, i.e. the distance between the piercing face 16 of the nut and thestop surface 15. The dimension denoted B is the shoulder height of thenut and constitutes from /3 to /2 of the pilot height A. The dimension Cis the pilot base or ledge height and is not less than 0.010 inch. Thedimension D is the groove height of the nut and is from /2 to /3 of thepilot height less 0.010 inch or the ledge height, whichever is greater.

Of these dimensions, the shoulder height is of extreme importanceinasmuch as this shoulder serves as the punch when the nut is utilizedas a pierce nut and the shoulder must be sufficiently heavy toaccommodate punching through the sheet metal without such deformationofthe nut as would interfere with the groove 30 or with the threadedaperture 20. The pilot base C is of such height as to serve toaccurately position the nut Within a prepierced hole when the nut isutilized as a clinch nut. The groove height D is suflicient toaccommodate the flow of sufiicient metal into the groove beneath theshoulders 21 to firmly aflix the nut to the plate when the nut isutilized as a pierce nut.

In that embodiment of the invention illustrated in FIG- URE 3 of thedrawings, it will be seen that the nut 10 is firmly grounded orsupported upon a base 40 contacting the undersurface 13 of the nut. Theplate 41 is intially interposed between the nut 10 and a die button 42having a swaging projection 43 surrounding a slug aperture 44 in thedie. Upon relative movement of the die button 42 of the nut 10, the nutpilot portion is forced through the plate 41, thus piercing an aperturefor the pilot portion. Subsequent further contact between the die buttonand the plate indents the plate, as at 45, as the plate is bottomed uponthe stop surfaces 15 of the nut and the plate is swaged, as at 46 intothe grooves 30. It will be seen that the ledge 25 prevents anysubstantial lateral flow of metal immediately adjacent the bottom of theaperture formed in the plate, and that this ledge serves to aid indirecting metal 46 into the groove 30.

In that embodiment of the invention illustrated in FIG- URES 4 and 5,the nut 10 is utilized as a clinch nut. As best illustrated in FIGURE 5of the drawings, the nut is firmly bottomed against a base or the like47 and a plate 48 having therein a pre-pierced hole 49 is thentelescoped over the pilot portion 12 of the nut. This pre-pierced hole49 is of the same shape as the nut pilot portion and is of the sametransverse dimension with a clearance of 0.010 inch in each lateraldimension. This hole is kept to a tolerance of 0 on the low side and of0.003 inch on the high side to accommodate Wear in the punch forming theaperture 49 in the plate 48. With the plate and the nut pre-assenibled,the nut is next contacted with a staking die 50 having a centralcircular aperture 51 of a diameter somewhat greater than the transversediameter of the nut and having a circular cutting edge 52 forming theapex of a frusto-conical staking surface 53 terminating in a laterallyoutwardly extending stop flange 54.

It will be noted from FIGURE 4 that the staking edge 52 contacts the nutpilot surface 16 only adjacent the corners thereof and that the stakingdie 50 is displaced to an extent sufiicient to indent the nut pilotcorners to an appreciable extent, as at 55. The inclined frusto-conicalsurface 53 displaces the nut metal laterally outwardly relative to thenut to displace the corners of the nut outwardly, as at 56, to overliethe corners of the aperture 49. Additionally, nut metal is displaced, asat 57, to fill the grooves 30 at the corners and to firmly establishlateral contact between the nut and the edges 49 of the plate aperture.

Thus, it will be appreciated that the present invention provides a newand novel method of staking a dual purpose pierce-clinch nut within apre-pierced hole in a panel or the like. Due to the presence of thepilot base or ledge surface 25, the nut is firmly piloted into theaperture 49, and this ledge prevents drifting of the nut toward one sideor the other of the aperture. Thus, the main disadvantage ofconventional pierce nuts is avoided.

Further, by staking only the corners of the nut, a sufficient force canbe exerted upon the nut pilot portion by the staking edge 52 tosubstantially completely fill the nut groove 30 therebeneath and toestablish firm nutpanelcontact.

I claim:

1. In amethod of installing a clinch nut in a panel having a polygonalaperture, the nut having a polygonal end pilot portion projectingthrough the panel aperture, flanges bottomed against the panel, grooveslocated in the panel aperture and a pilot base portion snugly fittinginto said aperture, the flanges and grooves being on opposite sides ofsaid pilot portion and said pilot base portion being between each ofsaid grooves and the adjacent flange, the steps of inserting said endpilot portion into said preformed aperture to an extent such that saidend pilot portion projects beyond one face of the panel and said flangesabut the other face of the panel, centering said nut in said aperture bythe snug fit of the pilot base portion in said aperture, laterallyoutwardly deforming the corners only of the nut end pilot portion tooverlie the plate adjacent said aperture and'to afiix the nut to thepanel, and displacing the so-deformed nut corners toward the nut flangesto flow a portion of each such nut corner into the corresponding nutgroove only at said corners and between the nut pilot base portion andthe pilot portion, said displaced nut corners and said pilot baseportion elfecting snug abutment between said nut and the edges of thepanel aperture at each corner thereof.

2. The method of installing a clinch nut in a panel having a preformedpolygonal aperture, the nut having a polygonal end pilot portion ofsubstantially the size and shape of the panel aperture, a pair offlanges spaced from the end pilot portion through a distance at least asgreat as the thickness of the panel, grooves immediately adjacent theend pilot portion, said flanges and said grooves being on opposite sidesof said end pilot portion,

and a pilot base portion of substantially the same shape and size as theend pilot portion and interposed between each of said grooves and theadjacent flange, respectively, the steps of inserting said nut pilotportion into said aperture to an extent such that said end pilot portionprojects beyond one face of said panel and said flanges abut the otherface of said panel, centering said nut in said aperture despite thepresence of said grooves within said aperture by the snug fit therein ofsaid pilot base portion, laterally outwardly deforming each of thecorners only of the end nut pilot portion to overlie the plate adjacentsaid aperture and to affix the nut to the panel, and displacing theso-deformed nut corners toward the nut flanges to force a portion ofeach nut corner into the corresponding nut groove only at said cornersand only between said end pilot portion and said pilot base portion, andto effect snug abutment between said nut and the edges of the panelaperture adjacent thereto.

References Cited by the Examiner UNITED STATES PATENTS 2,110,039 3/38Double. 2,707,322 5/55 Strain et al 29-432 2,749,606 a 6/56 Donahue29-432 2,750,660 6/56 Newcomb 29-432 2,784,930 3/57 Wernecke 29-432 X3,091,843 6/ 63 Double et a1 29--432 WHITMORE A. WILTZ, PrimaryExaminer.

JOHN F. CAMPBELL, Examiner.

1. IN A METHOD OF INSTALLING A CLINCH NUT IN A PANEL HAVING A POLYGONALAPERTURE, THE NUT HAVING A POLYGONAL END PILOT PORTION PROJECTINGTHROUGH THE PANEL APERTURE, FLANGES BOTTOMED AGAINST THE PANEL, GROOVESLOCATED IN THE PANEL APERTURE AND A PILOT BASE PORTION SNUGLY FITTINGINTO SAID APERTURE, THE FLANGES AND GROOVES BEING ON OPPOSITE SIDES OFSAID PILOT PORTION AND SAID PILOT BASE PORTION BEING BETWEEN EACH OFSAID GROOVES AND THE ADJACENT FLANGE, THE STEPS OF INSERTING SAID ENDPILOT PORTION INTO SAID PREFORMED APERTURE TO AN EXTENT SUCH THAT SAIDEND PILOT PORTION PROJECTS BEYOND ONE FACE OF THE PANEL AND SAID FLANGESABUT THE OTHER FACE OF THE PANEL, CENTERING SAID NUT IN SIAD APERTURE BYTHE SNUG FIT OF THE PILOT BASE PORTION IN SAID APERTURE, LATERALLYOUTWARDLY DEFORMING THE CORNERS ONLY OF THE NUT END PILOT PORTION TOOVERLIE THE PLATE ADJACENT SAID APERTURE AND TO AFFIX THE NUT TO THEPANEL, SAID DISPLACING THE SO-DEFORMED NUT CORNERS TOWARD THE NUTFLANGES TO FLOW A PORTION OF EACH SUCH NUT CORNER INTO THE CORRESPONDINGNUT GROOVE ONLY AT SAID CORNERS AND BETWEEN THE NUT PILOT BASE PORTIONAND THE PILOT PORTION, SAID DISPLACED NUT CORNERS AND SAID PILOT BASEPORTION EFFECTING SNUG ABUTMENT BETWEEN SAID NUT AND THE EDGES OF THEPANEL APERTURE AT EACH CORNER THEREOF.